Pumped Storage Boosts Reliability and Offsets Costs
The Lake Hodges facilities are part of the San Diego County Water Authority’s Emergency & Carryover Storage Projects & Facilities, a system of reservoirs, interconnected pipelines and pumping stations designed to make water available to the San Diego region in the event of an interruption in imported water deliveries.
To mitigate construction impacts from the Emergency & Carryover Storage Project, the Water Authority funded the acquisition of nearly 600 acres of upland habitat areas and created or enhanced nearly 40 acres of wetland habitat in San Diego County.
Construction of the facilities began in 2005, and operations began in 2012.
Facilities Overview
The facilities connect the city of San Diego’s Hodges Reservoir, also called Lake Hodges, to the Water Authority’s Olivenhain Reservoir. The connection provides the ability to store 20,000 acre-feet of water in Hodges Reservoir for emergency use. It also allows water to be pumped back and forth between Hodges Reservoir and Olivenhain Reservoir. From Olivenhain Reservoir, water can be distributed throughout the region.
The Hodges Inlet/Outlet Structure is located below the surface of Hodges Reservoir. The structure is connected to the pump station by a 200-foot-long tunnel. The pump station draws or discharges water from the reservoir through the inlet-outlet structure. A trash rack, located at the west end of the structure, prevents large debris from entering the pump station. On the west side of the pump station, water travels through a 10-foot diameter underground pipeline to the Olivenhain Reservoir, 1.25 miles away.
When water is transferred downhill from Olivenhain Reservoir into Hodges Reservoir, it generates up to 40-megawatts of peak hydroelectric energy, enough power to annually sustain nearly 26,000 homes. This energy helps offset facility operating costs and support future Water Authority projects. The facilities also help keep Hodges Reservoir at a more constant level during dry seasons, capture runoff during rainy seasons.
Want to learn more, dig deeper?
Lake Hodges Pumped Storage Facilities Fact Sheet
Key Facilities Components
Pipeline Connecting 2 Reservoirs
Pipeline Tunnel: a 10-foot diameter underground pipeline, contained in a 1.25 mile long tunnel, and connects the two reservoirs.
Hydro-Electric Power
Pump/Hydro Station: moves water back and forth between the two reservoirs and generates electricity.
Control of Electricity Transmission
Electrical Switchyard: provides electricity to the pump/hydro station and sends electricity from the pump/hydro station to a local transmission system.
Water Flow Between Storage & The Power Station
Inlet-outlet Structure: located below the water surface in Hodges Reservoir. It draws and discharges water between the Hodges Reservoir and the pump/hydro station.